Polluting Wood Stoves Go up in Smoke with Sole-Source Conversion Program

By Joel Karmazyn

The sole-source conversion program helped owners replace old coal stoves like the one pictured with new natural-gas furnaces.

Old coal stove ready for removal

Most of us take for granted the luxury of heating our homes with natural gas. But did you know that some homeowners within Utah’s PM2.5 nonattainment areas heat their homes solely with wood or coal? Thanks to a $500,000 appropriation from the 2014 Utah State Legislature, the Division of Air Quality (DAQ) was able to install central-heating systems in homes that were heated solely by wood or coal and registered with DAQ as a “sole-source residence.”

DAQ’s sole-source conversion project was completed in 2016, with 35 homes receiving new natural-gas furnaces, specialty heaters, or boilers.

Wood- and coal-burning devices are more polluting than other sources of heat. In 2016, DAQ conducted a wintertime wood-smoke study that collected PM2.5 measurements and analyzed them for a specific chemical marker from wood burning. Data analysis of these measurements indicate that emissions from wood burning contribute an appreciable amount of pollution during winter inversions in the PM2.5 nonattainment areas in northern Utah, even during mandatory no-burn periods.

Under our air quality rules, residents who use wood or coal as their sole source of heat are exempt from the burning restrictions we put in place during wintertime inversions. This exemption ensures that residents can heat their homes, but it doesn’t address the high emissions that come from these heating sources.

That’s where the sole-source conversion program came in.

Our office, through State Procurement, contracted with American Heating and Cooling for the sole-source conversion project. Tom Sanders from American Heating and Cooling and I inspected residences to assure that the home met the legal definition of a sole source. We then proceeded to design a conversion project that was agreeable to the homeowner. Many sole-source homes lacked ducting, a significant obstacle that often leads to some “creative” designs!

The sole-source conversion replaced old furnaces with new natural gas furnaces like the ones pictured.

New natural-gas furnace

Here’s an example of what we did. The wood stove pictured at the beginning of the blog was located in the basement of a log cabin in a residential neighborhood in the Wasatch Front and provided the sole source of heat. The sole-source conversion project included the installation of a high-efficiency (96 percent) natural-gas furnace. The project required some creative ducting to direct heat to all parts of this multi-level cabin, but we were able to successfully install a system that satisfied the needs of the homeowner and reduced the emissions to our airshed from the old wood stove.

We completed conversions in Box Elder, Salt Lake, Tooele, Utah, and Weber counties. All together, we installed 29 natural-gas or propane furnaces, five natural-gas specialty heaters, and one natural-gas boiler. We retired seven coal stokers and installed six new gas lines. The estimated combined emission reduction from the project was 4.6 tons per year.


The conversion program was a great success. We were able to decrease  solid-fuel emissions — both gases and particulates — that lead to poor air quality during inversion periods and provide financial assistance to homeowners who weren’t able to afford the costly upgrades necessary to convert from solid fuels to cleaner-burning forms of heating.

You can take the following simple steps to reduce the impacts of wood smoke, particularly during inversions:
  • Don’t burn wood on voluntary action days.

Joel KarmazynI am an environmental scientist at the Utah Division of Air Quality, where I am responsible for policy and planning of minor-source emissions. I enjoy traveling, hiking with my dog, and working in my vegetable garden.